WO2020006729A1

WO2020006729A1 - Methods and apparatus for group communication

Info

Publication number: WO2020006729A1
Application number: PCT/CN2018/094644
Authority: WO
Inventors: Yiqing Cao; Yan Li; Shuping Chen; Lu Gao; Zhimin Du; Hong Qiu; Bin Han
Original assignee: Qualcomm Incorporated
Priority date: 2018-07-05
Filing date: 2018-07-05
Publication date: 2020-01-09

Abstract

The present disclosure relates to methods and devices for a platooning group which may include a first user equipment (UE) and a group of UEs. In one aspect, the first UE can transmit an indication for one or more acknowledgement (ACK) resources for the group of UEs. The first UE may receive negative acknowledgements (NAKs) on the ACK resources from the group of UEs. The first UE can also determine whether to adjust a transmit power based on the NAKs. In another aspect, the first UE can determine an energy level of the NAKs and increase the transmit power or decrease a modulation and coding scheme (MCS) when the energy level is greater than a threshold. The first UE can also receive ACKs on the ACK resources, wherein each NAK and ACK comprises a corresponding UE identifier.

Description

METHODS AND APPARATUS FOR GROUP COMMUNICATION

Technical Field

The present disclosure relates generally to communication methods and systems, and more particularly, to methods and apparatus related to a group of devices in a wireless communication system including, e.g., a vehicular communication network.

Introduction

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is 5G New Radio (NR) . 5G NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT) ) , and other requirements. Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. There exists a need for further improvements in 5G NR technology. These improvements may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

SUMMARY

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

Various features and aspects related to communicating in a group (e.g., by an individual user equipment (UE) or a group of UEs) for a platooning group in a wireless communication system (e.g., including vehicular systems such as vehicle-to-vehicle (V2V) and/or vehicle-to-everything (V2X) networks) are described. In accordance with the methods and features described herein, a head (e.g., an individual UE) of a platooning group may use one or more resources (e.g., acknowledgement (ACK) resources) to transmit and/or receive a number of ACKs or negative acknowledgements (NAKs) from the group of UEs. The head of the platooning group can also determine whether to adjust a transmit power based on the number of ACKs or NAKs. By adjusting the transmit power, the platooning group head may help to manage the potential interference from neighboring groups within a certain range of the platooning group.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a first UE (e.g., a vehicle in a V2V/V2X network) which may be the head of a platooning group. The first UE may be configured to transmit an indication for one or more ACK resources for the group of UEs. In some aspects, the first UE may receive NAKs on the ACK resources from the group of UEs. The first UE can also determine whether to adjust a transmit power based on the NAKs. In other aspects, the first UE can determine an energy level of the NAKs and increase the transmit power or decrease a modulation and coding scheme (MCS) when the energy level is greater than a threshold. The first UE can also receive ACKs on the ACK resources, wherein each NAK and ACK comprises a corresponding UE identifier.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a diagram illustrating an example of a wireless communications system and an access network.

FIGs. 1B-1D are diagrams illustrating examples of some architecture options that may be used with the access network of FIG. 1A.

FIGs. 2A-2I are diagrams illustrating examples of a DL subframe, DL channels within the DL subframe, an UL subframe, and UL channels within the UL subframe, respectively, for a 5G/NR frame structure.

FIG. 3 is a diagram illustrating an example of a base station and user equipment (UE) in an access network.

FIG. 4 illustrates an example of communication between UEs in a platooning group.

FIG. 5 illustrates two different types of control messages and two different types of data messages that may be used for communication between UEs (e.g., vehicles) in some configurations.

FIG. 6 is a diagram illustrating transmissions between a group head and other group members.

FIG. 7 is a diagram illustrating transmissions between a group head and other group members.

FIG. 8 is a flowchart of a method of wireless communication.

FIG. 9 is a conceptual data flow diagram illustrating the data flow between different means/components in an exemplary apparatus.

FIG. 10 is a diagram illustrating an example of a hardware implementation for an apparatus employing a processing system.

FIG. 11 is a flowchart of a method of wireless communication.

FIG. 12 is a conceptual data flow diagram illustrating the data flow between different means/components in an exemplary apparatus.

FIG. 13 is a diagram illustrating an example of a hardware implementation for an apparatus employing a processing system.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements” ) . These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

By way of example, an element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs) , central processing units (CPUs) , application processors, digital signal processors (DSPs) , reduced instruction set computing (RISC) processors, systems on a chip (SoC) , baseband processors, field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

Accordingly, in one or more example embodiments, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise a random-access memory (RAM) , a read-only memory (ROM) , an electrically erasable programmable ROM (EEPROM) , optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

FIG. 1A is a diagram illustrating an example of a wireless communications system and an access network 100. The wireless communications system (also referred to as a wireless wide area network (WWAN) ) includes base stations 102, UEs 104, and an Evolved Packet Core (EPC) 160. The base stations 102 may include macro cells (high power cellular base station) and/or small cells (low power cellular base station) . The macro cells include base stations. The small cells include femtocells, picocells, and microcells.

The base stations 102 (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN) ) interface with the EPC 160 through backhaul links 132 (e.g., S1 interface) . In another example, the wireless communications system may comprise 5G Core (5GC) 190. In addition to other functions, the base stations 102 may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity) , inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS) , subscriber and equipment trace, RAN information management (RIM) , paging, positioning, and delivery of warning messages. The base stations 102 may communicate directly or indirectly (e.g., through the EPC 160 or 5GC 190) with each other over backhaul links 134 (e.g., X2 interface) . The backhaul links 134 may be wired or wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, the small cell 102'may have a coverage area 110'that overlaps the coverage area 110 of one or more macro base stations 102. A network that includes both small cell and macro cells may be known as a heterogeneous network. A heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs) , which may provide service to a restricted group known as a closed subscriber group (CSG) . The communication links 120 between the base stations 102 and the UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a base station 102 and/or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104. The communication links 120 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be through one or more carriers. The base stations 102 /UEs 104 may use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100 MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) used for transmission in each direction. The carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or less carriers may be allocated for DL than for UL) . The component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell) .

Certain UEs 104 may communicate with each other using device-to-device (D2D) communication link 192. The D2D communication link 192 may use the DL/UL WWAN spectrum. The D2D communication link 192 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) . D2D communication may be through a variety of wireless D2D communications systems, such as for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

The wireless communications system may further include a Wi-Fi access point (AP) 150 in communication with Wi-Fi stations (STAs) 152 via communication links 154 in a 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs 152 /AP 150 may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

The small cell 102'may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell 102'may employ NR and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP 150. The small cell 102', employing NR in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network.

A base station 102, whether a small cell 102'or a large cell (e.g., macro base station) , may include an eNB, gNodeB (gNB) or other type of base station. Some base stations, such as gNB 180 may operate in a traditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies, and/or near mmW frequencies in communication with the UE 104. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 may be referred to as an mmW base station. Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in the band may be referred to as a millimeter wave. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave. Communications using the mmW /near mmW radio frequency band has extremely high path loss and a short range. The mmW base station 180 may utilize beamforming 184 with the UE 104 to compensate for the extremely high path loss and short range.

The EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be in communication with a Home Subscriber Server (HSS) 174. The MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation as well as other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176. The IP Services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services. The BM-SC 170 may provide functions for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN) , and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to distribute MBMS traffic to the base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

In the 5GC example, the base stations 102, may be referred to as Next Generation RAN (NG-RAN) that interface with the 5GC 190 through backhaul links 193 (e.g., S1 interface) . The 5GC 190 may include a Access and Mobility Management Function (AMF) 192, other AMFs 194, a Session Management Function (SMF) 196, and a User Plane Function (UPF) 199. The AMF 192 may be in communication with a Unified Data Management (UDM) 191. The AMF 192 is the control node that processes the signaling between the UEs 104 and the 5GC 190. Generally, the AMF 192 provides QoS flow and session management. All user Internet protocol (IP) packets are transferred through the UPF 199. The UPF 199 provides UE IP address allocation as well as other functions. The UPF 199 is connected to the IP Services 197. The IP Services 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services.

The base station may also be referred to as a gNB, Node B, evolved Node B (eNB) , an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , a transmit reception point (TRP) , or some other suitable terminology. The base station 102 provides an access point to the EPC 160 or 5GC 190 for a UE 104. Examples of UEs 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA) , a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player) , a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device. Some of the UEs 104 may be referred to as IoT devices (e.g., parking meter, gas pump, toaster, vehicles, heart monitor, etc. ) . The UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

Referring again to FIG. 1A, in certain aspects, a first device (e.g., such as UE 104 which may be a vehicle or a device installed in a vehicle) may be configured to transmit indication for ACK resources for a group of devices (e.g., UEs 104 which may be vehicles or devices installed in vehicles) (198) . The first device may receive a first number of NAKs from the group of devices (198) . Additionally, the first device may determine whether to adjust a transmit power based on the first number of NAKs (198) . Various additional aspects and details of the methods and apparatus herein are discussed infra with respect to FIGs. 4-10. As discussed infra, various features of the methods described herein support communication related to a platooning group in V2V and/or V2X networks.

FIGS. 1B-1D are diagrams 100b, 100c, and 100d illustrating examples of non-standalone (NSA) architecture deployment which may be used in the access network of 100 of FIG. 1A. In some configurations, the UE 104 may simultaneously connect to a first base station (e.g., eNB 102) via a first radio access technology (RAT) and a second base station (e.g., gNB 180) via a second RAT, as shown in FIGS. 5A-5C. For example, the first RAT may comprise and/or support LTE wireless access technology, and the second RAT may comprise and/or support 5G NR wireless access technology.

FIG. 1B illustrates a first option (e.g., option 3x) of an NSA architecture deployment that may be used in the access network 100 in some configurations. In this option, base station 180 (e.g., gNB) may have an S1-U connection to the core network (e.g., EPC 160) via the SGW 166/PGW 172. Base station 102 (e.g., eNB) may have an S1-MME connection to the EPC 160 via the MME 162. This configuration may comprise a DC, split bearer. Thus, with this option, the data may go through both the first base station 102 via LTE and the second base station 180 via 5G NR. The data may combine, or merge at the second base station 180, because the dual connectivity split bearer is anchored at the second base station 180. The consolidated data may be sent to the core network EPC 160 by the second base station 180.

FIG. 1C illustrates a second option (e.g., option 3) of the NSA architecture deployment that may be used in the access network 100 in some configurations. In this option, data may similarly go through both the first base station 102 via LTE and the second base station 180 via 5G NR. However, in this example, the data may combine, or merge at the first base station 102 because the dual connectivity split bearer is anchored at the first base station 102. The consolidated data may be sent to the core network EPC 160 by the first base station 102.

FIG. 1D illustrates a third option (e.g., option 3a) of the NSA architecture deployment that may be used in the access network 100 in some configurations. In this option, the data may only go through the second base station 180, and the second base station 180 may send the data the core network EPC 160.

FIG. 2A is a diagram 200 illustrating an example of a DL subframe within a 5G/NR frame structure. FIG. 2B is a diagram 230 illustrating an example of channels within a DL subframe. FIG. 2C is a diagram 250 illustrating an example of an UL subframe within a 5G/NR frame structure. FIG. 2D is a diagram 280 illustrating an example of channels within an UL subframe. The 5G/NR frame structure may be FDD in which for a particular set of subcarriers (carrier system bandwidth) , subframes within the set of subcarriers are dedicated for either DL or UL, or may be TDD in which for a particular set of subcarriers (carrier system bandwidth) , subframes within the set of subcarriers are dedicated for both DL and UL. In the examples provided by FIGs. 2A, 2C, the 5G/NR frame structure is assumed to be TDD, with subframe 4 a DL subframe and subframe 7 an UL subframe. While subframe 4 is illustrated as providing just DL and subframe 7 is illustrated as providing just UL, any particular subframe may be split into different subsets that provide both UL and DL. Note that the description infra applies also to a 5G/NR frame structure that is FDD.

A resource grid may be used to represent the frame structure. Each time slot includes a resource block (RB) (also referred to as physical RBs (PRBs) ) that extends 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs) . The number of bits carried by each RE depends on the modulation scheme.

As illustrated in FIG. 2A, some of the REs carry reference (pilot) signals (RS) for the UE (indicated as R) . The RS may include demodulation RS (DM-RS) and channel state information reference signals (CSI-RS) for channel estimation at the UE. The RS may also include beam measurement RS (BRS) , beam refinement RS (BRRS) , and phase tracking RS (PT-RS) .

FIG. 2B illustrates an example of various channels within a DL subframe of a frame. The physical control format indicator channel (PCFICH) is within symbol 0 of slot 0, and carries a control format indicator (CFI) that indicates whether the physical downlink control channel (PDCCH) occupies 1, 2, or 3 symbols (FIG. 2B illustrates a PDCCH that occupies 3 symbols) . The PDCCH carries downlink control information (DCI) within one or more control channel elements (CCEs) , each CCE including nine RE groups (REGs) , each REG including four consecutive REs in an OFDM symbol. A UE may be configured with a UE-specific enhanced PDCCH (ePDCCH) that also carries DCI. The ePDCCH may have 2, 4, or 8 RB pairs (FIG. 2B shows two RB pairs, each subset including one RB pair) . The physical hybrid automatic repeat request (ARQ) (HARQ) indicator channel (PHICH) is also within symbol 0 of slot 0 and carries the HARQ indicator (HI) that indicates HARQ acknowledgement (ACK) /negative ACK (NAK) feedback based on the physical uplink shared channel (PUSCH) . The primary synchronization channel (PSCH) may be within symbol 6 of slot 0 within

subframes

0 and 5 of a frame. The PSCH carries a primary synchronization signal (PSS) that is used by a UE 104 to determine subframe/symbol timing and a physical layer identity. The secondary synchronization channel (SSCH) may be within symbol 5 of slot 0 within

subframes

0 and 5 of a frame. The SSCH carries a secondary synchronization signal (SSS) that is used by a UE to determine a physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a physical cell identifier (PCI) . Based on the PCI, the UE can determine the locations of the aforementioned DL-RS. The physical broadcast channel (PBCH) , which carries a master information block (MIB) , may be logically grouped with the PSCH and SSCH to form a synchronization signal (SS) /PBCH block. The MIB provides a number of RBs in the DL system bandwidth, a PHICH configuration, and a system frame number (SFN) . The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs) , and paging messages.

As illustrated in FIG. 2C, some of the REs carry demodulation reference signals (DM-RS) for channel estimation at the base station. The UE may additionally transmit sounding reference signals (SRS) in the last symbol of a subframe. The SRS may have a comb structure, and a UE may transmit SRS on one of the combs. The SRS may be used by a base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

FIG. 2D illustrates an example of various channels within an UL subframe of a frame. A physical random access channel (PRACH) may be within one or more subframes within a frame based on the PRACH configuration. The PRACH may include six consecutive RB pairs within a subframe. The PRACH allows the UE to perform initial system access and achieve UL synchronization. A physical uplink control channel (PUCCH) may be located on edges of the UL system bandwidth. The PUCCH carries uplink control information (UCI) , such as scheduling requests, a channel quality indicator (CQI) , a precoding matrix indicator (PMI) , a rank indicator (RI) , and HARQ ACK/NAK feedback. The PUSCH carries data, and may additionally be used to carry a buffer status report (BSR) , a power headroom report (PHR) , and/or UCI.

Other examples may have a different frame structure and/or different channels. A frame (10 ms) may be divided into 10 equally sized subframes (1 ms) . Each subframe may include one or more time slots. Each slot may include 7 or 14 symbols, depending on the slot configuration. For slot configuration 0, each slot may include 14 symbols, and for slot configuration 1, each slot may include 7 symbols. The number of slots within a subframe is based on the slot configuration and the numerology. For slot configuration 0, different numerologies 0 to 5 allow for 1, 2, 4, 8, 16, and 32 slots, respectively, per subframe. For slot configuration 1, different numerologies 0 to 2 allow for 2, 4, and 8 slots, respectively, per subframe. The subcarrier spacing and symbol length/duration are a function of the numerology. The subcarrier spacing may be equal to 2^μ*15 kKz, where μ is the numerology 0-5. The symbol length/duration is inversely related to the subcarrier spacing. FIGs. 2A, 2C provide an example of a slot configuration with 14 symbols per slot and numerology 0 with 1 slot per subframe. The subcarrier spacing is 15 kHz and symbol duration is approximately 66.7 μs.

FIG. 2E is a diagram 220 illustrating an example of a DL subframe within an example 5G/NR frame structure. FIG. 2F is a diagram 240 illustrating an example of an SS Block within a DL subframe within a 5G/NR frame structure. FIG. 2G is a diagram 260 illustrating an example of an UL subframe within a 5G/NR frame structure. FIG. 2H is a diagram 280 illustrating an example of a DM-RS configuration type within an UL subframe in an example for 5G/NR. Similar to the examples in FIGs. 2A and 2C, the 5G/NR frame structure may be FDD or may be TDD. In the examples provided by FIGs. 2E, 2G, the 5G/NR frame structure is assumed to be TDD, with subframe 4 a DL subframe and subframe 7 an UL subframe. While subframe 4 is illustrated as providing just DL and subframe 7 is illustrated as providing just UL, any particular subframe may be split into different subsets that provide both UL and DL. Note that the description infra applies also to a 5G/NR frame structure that is FDD.

As with the example of FIGs. 2A-2D, a resource grid may be used to represent the 5G NR frame structure. Each time slot includes an RB (also referred to as PRBs) that extends 12 consecutive subcarriers. The resource grid is divided into multiple REs. The number of bits carried by each RE depends on the modulation scheme. The example slot in FIGs. 2E and 2G comprise 14 OFDM symbols. There may be multiple slots in a subframe, e.g., based on the numerology used. Mini-slots may also be supported, e.g., with a mini-slot being as small as 2 OFDM symbols and having a variable length. Mini-slots may also be positioned asynchronously with a beginning of a slot.

FIG. 2E illustrates an example frame structure 220 for an uplink slot. The uplink slot may comprise CSI-RS. Any of a number of different CSI-RS patterns may be used for CSI-RS transmissions from a base station. FIG. 2I shows various examples of CSI-RS patterns that may be employed within a slot.

Example patterns

201, 202, 203, 204, 206, and 209 show examples in which CSI-RS may be transmitted only in a first symbol, e.g., symbol 0, of the slot.

Example patterns

205, 207, 208, 210, 211, and 212 illustrate examples in which CSI-RS may be transmitted only in symbol 0 and symbol 1 of a slot.

Example patterns

215 and 218 show examples in which CSI-RS is transmitted in the first four symbols of the slot.

Example patterns

213, 214, 218, and 217 illustrate patterns in which CSI-RS is transmitted in symbol 0, symbol 1, symbol 6, and symbol 7 of a slot. CSI-RS from different Code Division Multiplexed (CDM) groups may be comprised within a slot. Different patterns are used to indicate CSI-RS for different CDM groups. Thus,

example patterns

201, 202, and 203 illustrate example CSI-RS patterns for a single CDM group. Example patters 204, 205, and 208 show CSI-RS patterns for two different CDM groups. Example,

patterns

206, 210, and 215 illustrate example CSI-RS patterns for three different CDM groups, and so forth. For a given pattern, different CSI-RS components can be placed anywhere in the RB. For a given pattern, when different CSI-RS components are not shown in adjacent OFDM symbols, they can be placed anywhere in the slot. In a first example, CSI-RS may be transmitted by a single CDM group in a symbol 0, with the CSI-RS transmitted every 4 subcarriers. In another example, the CSI-RS may be transmitted in a single subcarrier in symbol 0. In another example, the CSI-RS may be transmitted two adjacent subcarriers in symbol 0.

FIG. 2F illustrates an example of various channels within a DL subframe of an SS Block in 5G NR. The SS Block may comprise a PSS, SSS, and PBCH. The SS block may comprise 4 OFDM symbols, as illustrated in the example of FIG. 2F. The SS block may comprise multiple RBs, e.g., 20 RBs corresponding to 240 subcarriers in frequency. In a slot of 14 symbols, two possible locations of the SS block include symbol 2-symbol 5, as illustrated in FIG. 2F and symbol 8-symbol 11. As illustrated, an SS block may comprise 1 symbol of PSS, 1 symbol of SSS, and at least two symbols of PBCH. The PSS, SSS, and PBCH may be time division multiplexed in consecutive symbols, e.g., for both a single beam example and multi-beam example. FIG. 2F illustrates an example time domain mapping, with PSS in one symbol, followed by a symbol comprising PBCH. The, a symbol of both SSS and PBCH is followed by a symbol comprising PBCH. Different subcarrier spacing for PSS/SSS may be used in connection with different frequency ranges. For example, a first subcarrier spacing for PSS/SSS may be used for a sub-6 frequency range a 15 kHz or 30kHz subcarrier spacing may be used. For a frequency range above the sub-6 range, a 120 kHz or 240 kHz subcarrier spacing may be used.

As illustrated in FIG. 2G, DM-RS may start at symbol 2 in a slot. While illustrated as only a single symbol the DM-RS may comprise both symbol 2 and symbol 3. There may be multiple configuration types for the DM-RS. A first configuration type, e.g., Configuration type 1, may transmit the DM-RS from two different ports, and within the same symbol, each subcarrier may have DM-RS from a different port. Configuration type 1 may include one OFDM symbol, as illustrated in FIG. 2G. In another example, the Configuration type 1 DM-RS may include two OFDM symbols, with the same port transmitting DM-RS within a subcarrier. Different phases of a complex sequence value for the DM-RS may be used in adjacent symbols in some patterns. In other patterns, the same phase may be used in adjacent symbols. Different phases of the complex sequence value for the DM-RS may be used in adjacent subcarriers in some patterns. In other patterns, the same phase may be used in adjacent subcarriers. FIG. 2H illustrates an example of Configuration type 2 DM-RS in which three different ports are used for the DM-RS. In Configuration type 2 DM-RS, every two subcarriers may carry DM-RS from one of three ports. As with Configuration 1, the DM-RS may be transmitted in a single symbol, e.g., at symbol 2, or may be transmitted in two symbols, e.g., symbol 2 and symbol 3. Uplink communication in the example of FIG. 2G may also comprise SRS. Rather than being located in the last symbol, as illustrated in FIG. 2C, the SRS can be configured to occupy a location within any of the last 6 symbols in a slot. The frequency domain starting position of the SRS allocation be configuration in a UE specific manner.

FIG. 3 is a block diagram of a base station 310 in communication with a UE 350 in an access network. In the DL, IP packets from the EPC 160 and/or 5GC 190 may be provided to a controller/processor 375. The controller/processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller/processor 375 provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIBs) , RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release) , inter radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression /decompression, security (ciphering, deciphering, integrity protection, integrity verification) , and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs) , error correction through ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs) , re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs) , demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1, which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing. The TX processor 316 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK) , quadrature phase-shift keying (QPSK) , M-phase-shift keying (M-PSK) , M-quadrature amplitude modulation (M-QAM) ) . The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a respective spatial stream for transmission.

At the UE 350, each receiver 354RX receives a signal through its respective antenna 352. Each receiver 354RX recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they may be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT) . The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 310. These soft decisions may be based on channel estimates computed by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the base station 310 on the physical channel. The data and control signals are then provided to the controller/processor 359, which implements layer 3 and layer 2 functionality.

The controller/processor 359 can be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller/processor 359 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the EPC 160 and/or 5GC 190. The controller/processor 359 is also responsible for error detection using an ACK and/or NAK protocol to support HARQ operations.

Similar to the functionality described in connection with the DL transmission by the base station 310, the controller/processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression /decompression, and security (ciphering, deciphering, integrity protection, integrity verification) ; RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by the base station 310 may be used by the TX processor 368 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antenna 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a respective spatial stream for transmission. In some configurations, the UE 350 (e.g., vehicle) may operate in a half-duplex mode where the UE 350 may only either transmit or receive at a given time. The half-duplex mode operation may be due to a given deployment scenario (e.g., such as when performing V2V and/or V2X communications) that may desire a half-duplex operation by devices, or due to UE capability (e.g., such as where the UE 350 may have a single TX/RX chain (354TX/RX) . In such configurations where the UE 350 may operate in the half-duplex mode, the UE 350 may not perform simultaneous transmission and reception.

The UL transmission is processed at the base station 310 in a manner similar to that described in connection with the receiver function at the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

The controller/processor 375 can be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer-readable medium. In the UL, the controller/processor 375 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE 350. IP packets from the controller/processor 375 may be provided to the EPC 160 and/or 5GC 190. The controller/processor 375 is also responsible for error detection using an ACK and/or NAK protocol to support HARQ operations.

Various features and aspects related to joining a platooning group (also referred to as the platoon) and communication related to the platooning group in a wireless communication system (e.g., including vehicular communication systems such as V2V, V2X, and/or enhanced V2X (eV2X) networks) are described herein. Platooning may be described as operating a group of vehicles in a closely linked manner such that the vehicles may move in a coordinated fashion, such as if connected by virtual strings. To maintain distance between the vehicles, the vehicles may share status information such as speed, heading, and intentions such as braking, acceleration, etc. By use of platooning, the distances between vehicles may be reduced, overall fuel consumption may be lowered (and thus fuel efficiency may be improved) , and the number of needed drivers may be reduced. In addition, an overall user experience may be improved with a sense of traveling in a group and being connected with others.

When forming or communicating within a platooning group, there should be a negotiation among the various members, e.g. devices or vehicles, within the platooning group. Communication or messages designed to either join or leave the platooning group can either be internal messages, meaning they are sent solely within the group, or external messages, meaning they are sent to other devices or vehicles as well. Communication or messages that focus on a group head leaving the group, or needing a new group head, can be sent internally within the group. Further, if a group head does not leave the group, but the group still needs a new group head, then these messages can be also be sent internally. Communication or messages regarding a new member joining the group can be external messages. Accordingly, in some aspects of the present disclosure, any device or vehicle can join the platooning group. Also, communication or messages concerning a member leaving the group can be sent internally. In other aspects of the present disclosure, any group member can leave the platooning group.

In some aspects, communication can be sent externally that works as an announcement and/or warning to non-group members. For instance, when a platoon is formed and operational, a vehicle that does not belong to the platoon should be aware of the existence of the platoon. Without any information about the existence or presence of the platoon, it is possible that the vehicle may move into the middle of the platoon and disrupt the operation of the platoon. Therefore, the existence of the platoon should be known to other vehicles beyond the communication range among vehicles of the same platoon. In this manner, platoon group information (e.g. direction, speed, etc. ) , can be sent as an external message or announcement in order to avoid any disruption to the group by other devices or vehicles. In other aspects, some platoon groups may not want any non-members to join the group. Indeed, some platoon groups may have limits on the amount of members.

As described herein, the head of a platooning group may use various messages described herein to announce the existence of the platooning group so that various other UEs (e.g., other vehicles) which may not belong to the platooning group can be aware of the presence of the platooning group. Such an announcement may help preventing disruption of the operation of the platooning group because the other vehicles hearing the announcement become aware of the platooning group and may avoid moving into the group (e.g., without approval) . Platooning groups herein can correspond to a number of different categorizations, such as public or private platooning groups. Further, internal communication or messages described herein can be referred to as private communication or messages. Likewise, external communication or messages described herein can be referred to as public communication or messages. Both public and private platooning groups can transmit or receive public or private communication or messages.

Communication or messages that is meant solely for group members can be transmitted as internal or private messages. For instance, communication or messages concerning group activities can be sent internally. One example of these messages are cooperative awareness messages (CAMs) . CAMs can comprise a number of different categories, including direction, orientation, speed, distance between members, etc.

When different devices or vehicles are traveling near one another, they can dynamically form a platoon. The platoon creator can be responsible for platoon management. The platoon manager or platooning group head can provide real-time updates surrounding traffic data reported by group members, and reported it to a road side unit (RSU) . At the same time, the platoon manager or head can receive RSU messages in real-time, which can include road conditions and traffic information from distances far away. The platoon manager or head can then share this information with platoon members. This information can also be shared along with group information, as all the platoon members can share the information within the group through V2V communication. All the platoon members can obtain information through several ways. For example, one way to share information cab ne within the platoon through V2Vcommunication. Another way to share information is if the information comes from a RSU, which can be relayed through the platoon manager or head. All the information obtained can be used to create high-precision dynamic driving maps. Any information exchanged between devices or vehicles within the group can be categorized as a type of “ask-response” information.

In accordance with the methods and features described herein, the head (e.g., an individual UE) of a platooning group may use one or more resources (e.g., ACK resources) to transmit and/or receive a number of ACKs or NAKs from the remaining UEs in the group. The head of the platooning group can also determine whether to adjust a transmit power based on the number of ACKs or NAKs. By adjusting the transmit power, the platooning group head may help to manage the potential interference from neighboring groups within a certain range of the platooning group.

The group head or manager should ensure that every group member, or a threshold number of group members, can receive the information communicated within the group. As mentioned here, this information can be referred to as group information. In addition, in order to reduce the interference from neighboring groups, the group head may use a power control mechanism to reduce power usage when transmitting or receiving communication or messages. The power control mechanism may help the group head to use a minimal amount of power while ensuring that group members reliably receive the communication. In one aspect, a decrease in transmission power can be used to a decrease inter-group interference for surrounding groups. If it is detected that there are no surrounding groups within a certain range of the platooning group, the group head can use a higher MCS which can increase the spectrum efficiency. The group head can also reduce the power even in the absence of surrounding groups. Thus, application of the power control mechanism may be independent of a detection of a nearby group.

FIG. 4 illustrates a diagram 400 of an example showing a platooning group 401 including a plurality of UEs (e.g., vehicles) . The platooning group (also simply referred to as the platoon) 401 may include

UEs

402, 404, and 406. For example,

UEs

402, 404, and 406 may all be considered to be members of the platoon 401, while UE 402 is also the head of the platoon 401. Information indicating the existence of the platoon 401 may be transmitted by UE 402 (e.g. as the head of the platoon 401) to other devices or UEs.

As indicated here, UE 402 may transmit (e.g., broadcast) an announcement message 410 to indicate the existence/presence of the platooning group 401. The platooning group 401 may be an open/public group which may be open to other UEs, or a private group (e.g., a tour group, family group, public safety group etc. ) which may only be open to an allowed set of UEs. The announcement message 410 can be a public or external message, such that it can be received by all UEs or devices, e.g. members and non-members, in the area, whether or not they are part of the group. Also, the announcement message 410 can be a private or internal message, such that it is only received by members of the platooning group.

As head of the platooning group, UE 402 can transmit an indication for one or more ACK resources 408 for the group members, e.g. UE 404 and UE 406. The one or more ACK resources can comprise one or more hybrid automatic repeat request (HARQ) resources. Group members, e.g. UE 404 and UE 406, can then transmit to UE 402 a number of ACKs or NAKs on the one or more ACK resources. UE 402 can also configure particular UE (s) from the group of UEs to report ACK/NAK. This enables the head to request an ACK/NAK report from certain UEs within the group. For example, the head UE 402 may request an edge UE or UEs that are closer to an edge to report the ACK/NAK. This may reduce the amount of resources used for the ACK/NAK. UE 402 can then receive the ACKs or NAKs from the group members and determine whether to adjust the transmit or transmission power for transmission based on the ACKs or NAKs. UE 402 can also determine an energy level of the ACKS or NAKs. In some aspects, if the energy level of the ACKS or NAKs is greater than a threshold energy level, then UE 402 can determine to increase the transmission power. Likewise, if the energy level of the ACKS or NAKs is less than a threshold energy level, then UE 402 can determine to decrease the transmission power. UE 402 can determine to increase or decrease the transmission power based on P _delta = a* (P _NAK –P _Threshold) + b, wherein a and b are constant coefficients, P _delta is power increasing step, P _NAK is the received power of NAK, and P _Threshold is the power of threshold.

The use of the energy level allows the NAKs to be sent on a common resource. UE 402 does not need to identify the source of each of the NAKs, and instead may make the determination of an amount of the group that did not receive a message based on an accumulated energy for the common NAK resource. The threshold energy level can be preconfigured, configured by UE 402, or configured by another entity such as a network node. Moreover, if the energy level of the ACKS or NAKs is greater than a threshold energy level, then UE 402 can determine to decrease an MCS. The MCS may be lowered independently from adjusting the transmission power or may be lowered while also increasing the transmission power. Additionally, UE 402 can use a power control mechanism to control the transmission power of communication or messages within the platooning group 401.

As mentioned supra, group members, e.g. UE 404 and UE 406, can transmit ACKS or NAKs to the group head, e.g. UE 402. In some aspects, the amount of ACKS or NAKs can be different, while in other aspects the amount of ACKS or NAKs can be the same. UE 402 can receive a number of ACK (s) or NAK (s) from UE 404 and UE 406, wherein each of the NAKs and ACKs comprises a corresponding UE identifier. This will enable the head UE to identify individual UEs from within the group that are not accurately receiving the communication from the head. Additionally, it enables the head UE to determine a specific number of UEs that are not accurately receiving the communication from the head UE. In some aspects, when the amount of NAKs received from the group members is above a certain threshold number, and/or when the amount of ACKs received from the group members is below a certain threshold number, the group head can determine to increase the transmission power. Likewise, when the amount of NAKs received from the group members is above a certain threshold number, and/or when the amount of ACKs received from the group members is below a certain threshold number, the group head can determine to decrease an MCS. UE 402 can also configure at least one UE from the group of UEs to report an ACK or a NAK, wherein the at least one UE can comprise an edge UE of the group of UEs.

As with the example based on an energy level rather than a UE identifier, the MCS may be adjusted independently from adjusting the transmission power or may be adjusted while also adjusting the transmission power. The transmission power can be decreased, and/or the MCS may also be increased when the NAKs are above, or the ACKs are below, a threshold number. The number of NAKs or ACKs can be determined based on the corresponding UE identifier comprised in each of the NAKs or ACKs. This enables the head UE to identify each UE for which it receives an ACK or a NAK. The UE can then determine the number of UEs that received the communication that prompted the ACK or NAK and the number of UEs that did not accurately receive the communication.

Additionally, when the amount of NAKs received from the group members is below a certain threshold number, or when the amount of ACKs received from the group members (e.g. UE 404 and UE 406) is above a certain threshold number, the group head (e.g. UE 402) can determine to decrease the transmit or transmission power. Similarly, when the amount of NAKs received from the group members is below a certain threshold number, or when the amount of ACKs received from the group members is above a certain threshold number, the group head can determine to increase an MCS. Correspondingly, the transmission power can be increased, or the MCS can be decreased when the NAKs are below, or the ACKs are above, a threshold number. The threshold number can be based on a threshold energy level or a corresponding UE identifier for comprised in each of the NAKs or ACKs. Also, each of NAKs or ACKs can be scrambled with the corresponding UE identifier. The corresponding UE identifier can be indicated to the group head based on the corresponding resource used to transmit and/or receive each of the NAKs or ACKs.

As mentioned herein, UE 402 can comprise a vehicle 402 and UE 404 and UE 406 can comprise vehicle 404 and vehicle 406, respectively. As further mentioned above, vehicles 402/404/406 can travel together in a platooning group 401. Vehicles 402/404/406 (e.g. UEs 402/404/406) and platooning group 401 can be part of a V2V communication network. Further, the movement of the vehicles 402/404/406 can be coordinated based on communication in the V2V communication network.

As group head, UE 402 can determine whether one or more additional groups of UEs are within a certain distance or area of the platooning group 401. For instance, UE 402 can determine whether additional groups are within a threshold range of the platooning group. When determine whether additional groups are within a threshold range of the platooning group, UE 402 may detect one or more groupcasting message (s) from the one or more additional groups of UEs or message (s) from additional networks. UE 402 can determine to increase an MCS or decrease the transmission power when one or more additional groups of UEs are not within the threshold range of the platooning group. Also, UE 402 can decrease an MCS or increase the transmission power when additional groups of UEs are not within the threshold range. Moreover, UE 402 can increase or decrease the MCS or transmit power when additional groups of UEs are within a threshold range.

As mentioned herein, the group head should make sure each group member correctly receives any transmitted group information. Group members can transmit an ACK and/or NAK to the group head in order confirm the group information was received. In some aspects, group members can transmit an ACK and/or NAK to help obtain or provide group information. As discussed supra, the group head can sends the ACK resources and the group member send the corresponding ACK and/or NAK. The group members can send the ACK and/or NAK to the group head on the resources allocated. As further mentioned herein, a reduction of unnecessary transmission power can help to reduce the interference from surrounding groups.

FIG. 5 is a diagram 500 illustrating two types of control messages and two types of data messages that may be used for communication between UEs (e.g., vehicles) . As illustrated in FIG. 5, in some aspects, two types of control messages are supported, e.g., control message type-1 510 and control message type-2 520, and two types of data messages are supported, e.g., data message type-1 530 and data message type-2 540. The first type of control message (e.g., control message type-1) 510 may be transmitted by individual UEs (e.g., members and the head of a platooning group, as well as other individual non-member UEs) . The second type of control message (e.g., control message type-2) 520 may be transmitted only by the head of a platooning group. Likewise, the first type of data message (e.g., data message type-1) 530 may be transmitted by individual UEs (e.g., members and head of a platooning group, as well as other individual non-member UEs) , whereas the second type of data message (data message type-2) 540 may be transmitted only by the head of a platooning group.

Control message type-1 510 may include, for example, one or more of the following types of information: an indication to form or not form a platooning group, an indication to be or not be the head of a platooning group, a query or invitation to join a platooning group, transmission resources for the first type of data message (e.g., data message type-1) , and transmission parameters for the first type of data message. For example, a control message type-1 510 may indicate transmission resources on which a corresponding data message type-1 530 may be transmitted. The transmission resources may comprise one or more of time, frequency, and/or spatial resources. Similarly, the control message type-1 510 may indicate one or more parameters for the corresponding data message type-1 530. For example, the parameters for the first type of data message comprise one or more of an MCS, a new data indicator, and/or a retransmission indicator. As another example, the control message type-1 510 may include the vehicle’s speed and/or position. The control message type-1 510 may include a transmit power for the UE, e.g., a transmit power at which the UE transmits communication to the group of UEs.

Control message type-2 520 transmitted by a UE (e.g., group head) may include, for example, one or more of the following information: a group identifier of a platooning group, transmission resources for the second type of data message (e.g., data message type-2 540) , transmission parameters for the second type of data message, and a HARQ resource indicator. For example, the indicated transmission resources for the second type of data message may comprise one or more of time, frequency, and/or spatial resources, and the indicated transmission parameters may comprise one or more of an MCS, and a retransmission indicator.

Data message type-1 530 transmitted by a UE may include, for example, information indicating one or more of: vehicle information corresponding to the transmitting UE such as speed of the UE, direction of the UE, position of the UE etc., a group identifier for a platooning group when the UE is requesting to join the platooning group, and an ACK and/or NAK to a group head (e.g., in response to a message from the group head) . For example, with reference to FIG. 4, the indication for one or more ACK resources 408 transmitted by the head UE 402 may be the data message type-1 530.

Data message type-2 540 transmitted by a UE (e.g., group head) may include one or more of: information indicating a need for a new platooning group head; information for a platooning group such as a group identifier, a speed of the platooning group, a direction of the platooning group, positioning of the platooning group, a braking indication or instruction, and an acceleration indication or instruction, information indicating an acceptance of a request to join the platooning group; information for a platooning group such as at least one group member identifier, a number of members in the platooning group, and a route for the platooning group, and/or inter-vehicle distance information. Messages such as this can be used in an open group concept. From the perspective of a receiving UE, both types of control messages and data messages may be accessible by the receiving UE whether the receiving UE is the group head, a member, or a non-member UE.

As mentioned above, the group head may transmit a control message that includes group information and ACK resources to the other group members. This message may also include an indicator for HARQ transmission resources, such as time, frequency, and/or spatial resources through antennas. The group members may transmit a one bit NAK on an assigned ACK resource. In some aspects, the assigned ACK resources are the same for all group members. In these aspects, as the ACK resources are the same, the group head cannot tell where the NAK is being sent from. Accordingly, it may be difficult for the group head to determine when a group member is not receiving the assigned ACK resources.

In order to determine whether group members are not receiving the assigned ACK resources, the group head can compare the NAK energy level at this assigned resource. In one aspect, if the NAK energy level is larger than a threshold, then the group head received the NAK, so a group member received the assigned ACK resources. If the accumulated NAK energy is strong enough, e.g. if it is larger than a threshold energy level, then the group head may increase the transmission power or lower the MCS. In some aspects, if the transmission power is increased, this can cause more interference to surrounding groups. If the MCS is reduced, then the communication can fall into a lower signal-to-noise (SNR) region. In this manner, group members can more easily decode the messages.

In some aspects, the threshold energy level can correspond to NAKs or ACKs from a threshold or certain number of group members (e.g., UEs) . As mentioned herein, the ACKs or NAKs may be used to adjust the transmission power for ongoing communication by group members, e.g., data and/or control messages, as mentioned in connection with FIG. 5. As indicated supra, the group head can determine to increase the transmit power when the energy level of an amount of NAKs received, within a predetermined time period, is greater than a threshold energy level. In some aspects, if the energy level from the amount of ACKs or NAKs received by the group head is lower than a threshold, the group head can decrease the transmission power. In further aspects, if the energy level from the amount of ACKs or NAKs received by the group head is greater than or equal to a threshold, the group head can increase the transmission power.

FIG. 6 is a diagram illustrating transmissions between a group head (e.g. UE 602) and other group members (e.g. UEs 604) . For instance, UE 602 can transmit 610 an indication for one or more ACK resources and group information 611 to the UEs 604. The one or more ACK resources can comprise one or more HARQ resources, e.g., as described in connection with the example of FIG. 5. Group members, e.g. UEs 604, can receive the indication for ACK resources and group information 620, as described with the example of FIG. 4. UE 602 can also configure, at 612, particular UE (s) from the group of UEs 604 to report ACK/NAK. This enables the head to request an ACK/NAK report from certain UEs within the group. For example, the head UE 602 may request an edge UE or UEs that are closer to an edge to report the ACK/NAK. This may reduce the amount of resources used for the ACK/NAK. Head UE 602 may transmit a message 621 to the group 604. The message may comprise control and/or data, as described in connection with FIG. 5 In response to the message 621, each UE in the group 604 can transmit 630 to UE 402 an ACK or a NAK 631 on the one or more ACK resources, depending on whether the UE correctly received the message 621 from the head UE 602. UE 602 can then receive 640 the NAKs from the group members. At 650, UE 602 can determine an energy level of the ACKS or NAKs. If the energy level of the NAKs is greater than a threshold energy level, then UE 602 can determine 660 to increase the transmission power or decrease an MCS. Likewise, if the energy level of the NAKs is less than a threshold energy level, then UE 602 can determine 660 to decrease the transmission power or increase an MCS. The increased/decreased transmit power or decreased/increased MCS 661 can be indicated to the group 604 by UE 602. At 671, UE 602 can transmit control and/or data messages with adjusted transmission power and/or MCS. The threshold energy level can be preconfigured, configured by UE 602, or configured by another entity such as a network node. Additionally, UE 602 can use a power control mechanism to control the transmission power of communication or messages within the platooning group. UE 602 can determine to increase or decrease the transmission power based on P _delta = a* (P _NAK –P _Threshold) + b, wherein a and b are constant coefficients, P _delta is power increasing step, P _NAK is the received power of NAK, and P _Threshold is the power of threshold.

As mentioned in connection with the example of FIG. 4, UE 602 can comprise a vehicle 602 and UEs 604 can comprise vehicles 604, respectively. As further mentioned in connection with FIG. 4, vehicles 602/604 can travel together in a platooning group. Vehicles 602/604 (e.g. UEs 602/604) and the platooning group can be part of a V2V communication network. Moreover, the movement of the vehicles 602/604 can be coordinated based on communication in the V2V communication network.

As group head, UE 602 can determine whether one or more additional groups of UEs are within a certain threshold range of the platooning group, as mentioned in connection with FIG. 4. When determining whether one or more additional groups of UEs are within a threshold range of the platooning group, UE 602 can detect one or more groupcasting messages from the one or more additional groups of UEs or message (s) from additional networks. UE 602 can determine to increase an MCS and/or decrease the transmission power when one or more additional groups of UEs are not within the threshold range. Also, UE 602 can increase an MCS or decrease the transmission power when additional groups of UEs are within the threshold range.

As mentioned herein, group members can send an ACK and/or NAK to the head on assigned or allocated resources, e.g. ACK resources. Additionally, the ACK and/or NAK can be transmitted by the group member along with a corresponding group identifier. In some aspects, the group identifier can be part of the message including the ACK/NAK or be scrambled to the message. As discussed in connection with FIG. 5, the message can be a data message, e.g., data message type-1. By scrambling the group identifier, it can save the payload size of the message. Further, the group identifier can be part of the signaling or communication which may reduce any blind decoding by the group head.

Within a predetermined time period, if the group head cannot receive the ACK and/or NAK from all the group members, the group head may need to increase the transmission power or reduce the MCS of the assigned or allocated resources. In some aspects, the group head can determine which group member is not receiving the assigned resources or messages. As mentioned supra, although the ACK or NAK may not identify an individual member, each group identifier transmitted with the ACK or NAK can correspond to an individual group member. Accordingly, if the group head does not receive a group identifier from a certain group member, then the group head can determine that the certain group member did not receive the assigned resources or messages. By this determination, the group head can also determine which group members are experiencing interference or noise.

As mentioned herein, reducing a power to transmit the one or more ACK resources can reduces the interference between the group head and the other group members. The one or more ACK resources can comprise a plurality of group information. As mentioned above, the group head can transmit the ACK resources, as well as transmit the data and/or control messages. Furthermore, the amount of ACKs or NAKs received by the group head can correspond to an amount of ACK or NAK energy.

FIG. 7 is a diagram illustrating transmissions between a group head (e.g. UE 702) and other group members (e.g. UEs 704) . For example, UE 702 can transmit 710 an indication 711 for one or more ACK resources and group information to the UEs 704. The one or more ACK resources can comprise one or more HARQ resources, as described in connection with the example of FIG. 5. Group members, e.g. UEs 704, can receive the indication for ACK resources and group information 720, as described with the example of FIG. 4. UE 702 can also configure, at 712, particular UE (s) from the group of UEs 604 to report ACK/NAK. This enables the head to request an ACK/NAK report from certain UEs within the group. For example, the head UE 702 may request an edge UE or UEs that are closer to an edge to report the ACK/NAK. This may reduce the amount of resources used for the ACK/NAK. Head UE 702 may transmit a message 721 to the group members 704. The message may comprise control and/or data, as described in connection with FIG. 5 In response to the message 721, each UE in the group 704 can transmit 730 to UE 702 an ACK and/or NAK 731 on the one or more ACK resources, depending on whether the UE correctly received the message 721 from the head UE 702. UE 702 can then receive 740 the ACKs and/or NAKs from the group members, as mentioned in connection with FIG. 4. Each of the ACKs and/or NAKs can comprise a corresponding UE identifier.

At 750, UE 702 can also determine the amount of ACKs and/or NAKs. If the amount of NAKs is greater than, or the amount of ACKs is less than, a threshold number, then UE 702 can determine 760 to increase the transmission power or decrease an MCS. Correspondingly, the transmission power can be decreased or the MCS can be increased when the amount of NAKs is less than, or the amount of ACKs is greater than, a threshold number. UE 702 can also determine to increase or decrease the transmission power based on P _delta = a* (P _NAK –P _Threshold) + b, wherein a and b are constant coefficients, P _delta is power increasing step, P _NAK is the received power of NAK, and P _Threshold is the power of threshold. UE 702 can also configure at least one UE from the group of UEs to report an ACK or a NAK, wherein the at least one UE can comprise an edge UE of the group of UEs. The number of NAKs or ACKs can be determined based on the corresponding UE identifier comprised in each of the NAKs or ACKs. The increased transmit power or decreased MCS 761 can be indicated to the group members 704 by UE 702. At 771, UE 702 can transmit control and/or data messages with adjusted transmission power and/or MCS.

The threshold number can be preconfigured, configured by UE 702, or configured by another entity such as a network node. The threshold number can also be based on a threshold energy level or a corresponding UE identifier for comprised in each of the NAKs or ACKs. Also, each of NAKs or ACKs can be scrambled with the corresponding UE identifier. The corresponding UE identifier can be indicated to the group head based on the corresponding resource used to transmit and/or receive each of the NAKs or ACKs. Also, UE 702 can use a power control mechanism to control the transmission power of communication or messages within the platooning group.

As mentioned in connection with the example of FIG. 4, UE 702 can comprise a vehicle 702 and UEs 704 can comprise vehicles 704, respectively. As further mentioned in connection with FIG. 4, vehicles 702/704 can travel together in a platooning group. Vehicles 702/704 (e.g. UEs 702/704) and the platooning group can be part of a V2V communication network. Moreover, the movement of the vehicles 702/704 can be coordinated based on communication in the V2V communication network.

As group head, UE 702 can determine whether one or more additional groups of UEs are within a certain threshold range of the platooning group, as mentioned in connection with FIG. 4. UE 702 can determine to increase an MCS and/or decrease the transmission power when one or more additional groups of UEs are not within the threshold range. When determining whether one or more additional groups of UEs are within a threshold range of the platooning group, UE 702 can detect one or more groupcasting messages from the one or more additional groups of UEs or message (s) from additional networks. Also, UE 702 can increase an MCS or decrease the transmission power when additional groups of UEs are within the threshold range.

FIG. 8 is a flowchart 800 of a method of wireless communication. The method may be performed by a UE (e.g.,

UE

104, 182, 350, 402, 602, 702, apparatus 902) communicating with group UEs (e.g.,

UEs

104, 180, 404, 406, 604, 704) . Optional aspects are illustrated with a dashed line. As mentioned in connection with the example of FIG. 4, the UE can comprise a vehicle and the group UEs can comprise vehicles, respectively. As further mentioned in connection with FIG. 4, these vehicles can travel together in a platooning group. The vehicles (e.g. UE and group UEs) and the platooning group can be part of a V2V communication network. Moreover, the movement of the vehicles can be coordinated based on communication in the V2V communication network. The UE can use a power control mechanism to control the transmission power of communication or messages within the platooning group.

At 802, the UE can transmit an indication for one or more ACK resources and group information to the group UEs. The one or more ACK resources can comprise one or more HARQ resources, e.g., as described in connection with the example of FIG. 5. Group member UEs can receive the indication for ACK resources and group information, as described with the example of FIG. 4.

At 803, the UE may configure at least one UE from the group of UEs to report ACK/NAK. This enables the head to request an ACK/NAK report from certain UEs within the group, e.g., UE (s) that are closer to an edge of the group. Thus, the head may also identify which UEs within the group are closer to an edge and may configure the identified UEs for ACK/NAK reporting based on the one or more ACK resources indicated at 802.

The UE may transmit communication with the group, e.g., including data and/or control messages as described in connection with FIG. 5. Group member UEs can transmit to the UE an amount of ACKs or NAKs on the one or more ACK resources indicated at 802. At 804, UE can receive the amount of ACKs and/or NAKs from the group members. Thus, the UE may receive a first number of NAKs from the group of UEs at 804.

Then, the UE determines whether to adjust a transmit power for transmissions based on the first number of NAKs received, at 804, from the group of UEs on the one or more resources. The determination may be made in various ways. For example, at 806, UE can determine an energy level of the first number of NAKs received on the one or more ACK resources. At 810, the UE may determine if the energy level of the NAKs is greater than a threshold energy level. If the energy level of the NAKs is greater than a threshold energy level, the UE increases the transmission power or decrease an MCS, as shown in step 814. Correspondingly, the transmission power can be decreased or the MCS can be increased, e.g., at 818, when the energy level of the first number of NAKs is less than a threshold energy level, or the energy level of ACKs is greater than, a threshold number. The UE can determine to increase or decrease the transmission power, at 814, based on P _delta = a* (P _NAK –P _Threshold) + b, wherein a and b are constant coefficients, P _delta is power increasing step, P _NAK is the received power of NAK, and P _Threshold is the power of threshold. This example of a power threshold enables the head UE to determine an amount of NAKs received without individually identifying which UEs sent the ACK (s) /NAK (s) .

The threshold energy level can be preconfigured, configured by the UE, or configured by another entity such as a network node.

The ACK (s) /NAK (s) received at 804 may comprise a corresponding UE identifier. Thus, the UE may receive, on the one or more resources, a second number of ACKs from the group of UEs, wherein each of the first number of NAKs and second number of ACKs comprises a corresponding UE identifier. At 808, the UE may alternatively determine the amount of ACKs and/or NAKs, wherein the first number of NAKs and/or the second number of ACKs are determined based on the corresponding UE identifier comprised in each of the first number of NAKs and the second number of ACKs. At 812, the UE determines if the amount of NAKs is greater than, or the amount of ACKs is less than, a threshold number. If the amount of NAKs is greater than, or the amount of ACKs is less than, a threshold number, then the UE can increase the transmission power or decrease an MCS, as shown in step 816. Correspondingly, the transmission power can be decreased or the MCS can be increased, e.g., at 820, when the amount of NAKs is less than, or the amount of ACKs is greater than, a threshold number. In another example of NAKs or ACKs can be scrambled with the corresponding UE identifier. The corresponding UE identifier can be indicated to the group head based on the corresponding resource used to transmit and/or receive each of the NAKs or ACKs. The number of NAKs or ACKs can be determined based on the corresponding UE identifier comprised in each of the NAKs or ACKs. Thus, the head UE may determine a number of NAKs by identifying NAKs sent by individual UEs in the group based on the UE identifier.

The threshold number can be preconfigured, configured by the UE, or configured by another entity such as a network node.

As group head, the UE may also adjust a transmission power and/or MCS for the group based on the presence of other groups of UEs and/or other networks. Thus, the UE can determine, at 822, whether one or more additional groups of UEs are within a certain threshold range of the platooning group, as mentioned in connection with FIG. 4. In one example, the UE can detect one or more groupcasting messages from an additional group of UEs. For example, the groupcasting message may comprise one of the types of messages described in connection with FIG. 5, e.g., a type 2 data message 540. Based on the groupcasting message, the UE may determine whether or not the additional group of UEs is within a threshold range that would lead to an adjustment of the transmission power for the group. In another example, the head UE may detect a message from an additional network. Based on the message, the UE may determine whether or not the additional network is within a threshold range that would lead to an adjustment of the transmission power for the group. The UE can determine to increase an MCS and/or decrease the transmission power, at 826, when one or more additional groups of UEs are not within the threshold range. Also, the UE can decrease an MCS or increase the transmission power, at 824, when additional groups of UEs are within the threshold range.

When the head determines at 814, 816, 818, and/or 820 to adjust the transmit power and/or MCS for the group of UEs, the head may indicate the adjustment to the group of UEs. The head may also transmit communication to the group of UEs based on the adjusted transmit power and/or adjusted MCS.

FIG. 9 is a conceptual data flow diagram 900 illustrating the data flow between different means/components in an exemplary apparatus 902. The apparatus may be a UE. The apparatus includes a ACK resource component 904 that is configured to transmit an indication for one or more ACK resources and group information to group UEs 950, e.g., via transmission component 904. The apparatus also includes an ACK/NAK component 916 that is configured to receive an amount of ACKs and/or NAKs on the one or more ACK resources, e.g., via reception component 906. Additionally, the apparatus includes an energy determination component 908 that is configured to determine the energy level of the received NAKs. If the energy level of NAKs is greater than a threshold energy level, energy determination component 908 determines to increase the transmit power and/or decrease an MCS. Similarly, if the energy level of the NAKs is below the threshold energy level, the energy determination component 910 may determine to decrease the transmit power and/or increase the MCS. The apparatus further includes an ACK/NAK determination component 910 that is configured to determine an amount of ACKs or NAKs. If the amount of ACKs or NAKs is greater than a threshold amount, ACK/NAK determination component 910 determines to increase the transmit power or decrease an MCS. Similarly, if the amount of the NAKs is below the threshold amount, the energy determination component 910 may determine to decrease the transmit power and/or increase the MCS. Each ACK/NAK may include a UE identifier, which may be identified, e.g., by UE ID component 918 to enable the ACK/NAK determination component 910 to determine the number of ACKs/NAKs. The apparatus can also include an ACK resource component 914 that is configured to transmit or indicate the ACK resources. Moreover, the apparatus includes a power and MCS component 912 that is configured to increase the transmit power or decrease an MCS, e.g., including determining whether to adjust the transmit power based on the determinations of ACK/NAK determination component 910 and/or energy determination component 908. The transmit power adjustment may be based on whether other groups are nearby. Thus, the apparatus may include a surrounding group component 920 configured to determine whether one or more additional groups of UEs are within a threshold range of the platooning group.

The apparatus may include additional components that perform each of the blocks of the algorithm in the aforementioned flowcharts of FIGs. 6-8. As such, each block in the aforementioned flowcharts of FIGs. 6-8 may be performed by a component and the apparatus may include one or more of those components. The components may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by a processor configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof.

FIG. 10 is a diagram 1000 illustrating an example of a hardware implementation for an apparatus 902'employing a processing system 1014. The processing system 1014 may be implemented with a bus architecture, represented generally by the bus 1024. The bus 1024 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 1014 and the overall design constraints. The bus 1024 links together various circuits including one or more processors and/or hardware components, represented by the processor 1004, the

components

904, 906, 908, 910, 912, 914, 916, 918, 920, and the computer-readable medium /memory 1006. The bus 1024 may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The processing system 1014 may be coupled to a transceiver 1010. The transceiver 1010 is coupled to one or more antennas 1020. The transceiver 1010 provides a means for communicating with various other apparatus over a transmission medium. The transceiver 1010 receives a signal from the one or more antennas 1020, extracts information from the received signal, and provides the extracted information to the processing system 1014, specifically the reception component 906. In addition, the transceiver 1010 receives information from the processing system 1014, specifically the transmission component 904, and based on the received information, generates a signal to be applied to the one or more antennas 1020. The processing system 1014 includes a processor 1004 coupled to a computer-readable medium /memory 1006. The processor 1004 is responsible for general processing, including the execution of software stored on the computer-readable medium /memory 1006. The software, when executed by the processor 1004, causes the processing system 1014 to perform the various functions described supra for any particular apparatus. The computer-readable medium /memory 1006 may also be used for storing data that is manipulated by the processor 1004 when executing software. The processing system 1014 further includes at least one of the

components

904, 906, 908, 910, 912, 914, 916, 918, 920. The components may be software components running in the processor 1004, resident/stored in the computer readable medium /memory 1006, one or more hardware components coupled to the processor 1004, or some combination thereof. The processing system 1014 may be a component of the UE 350 and may include the memory 360 and/or at least one of the TX processor 368, the RX processor 356, and the controller/processor 359.

In one configuration, the apparatus 902/902'for wireless communication includes means for transmitting an indication for one or more ACK resources for a group of UEs. The apparatus can also include means for receiving, on the one or more ACK resources, a first number of NAKs from the group of UEs. Additionally, the apparatus can include means for determining whether to adjust a transmit power based on the first number of NAKs received on the one or more ACK resources. The apparatus can include means for determining an energy level of the first number of NAKs on the one or more ACK resources, wherein the first UE determines to increase the transmit power when the energy level of the first number of NAKs is greater than a threshold energy level. Further, the apparatus can include means for determining to decrease a MCS when the energy level of the first number of NAKs is greater than the threshold energy level. The apparatus can also include means for configuring at least one UE from the group of UEs to report an ACK or a NAK. The apparatus can also include means for receiving, on the one or more ACK resources, a second number of ACKs from the group of UEs, wherein each of the first number of NAKs and second number of ACKs comprises a corresponding UE identifier. The apparatus can also include means for determining an energy level of the first number of NAKs on the one or more ACK resources, wherein the first UE determines to decrease the transmit power when the energy level of the first number of NAKs is less than a threshold energy level. Moreover, for the means for determining whether one or more additional groups of UEs are within a threshold range of the platooning group, the apparatus can also include means for determining to increase an MCS when the one or more additional groups of UEs are not within the threshold range of the platooning group. Also, for the means for determining whether one or more additional groups of UEs are within a threshold range of the platooning group, the apparatus can also include means for detecting one or more groupcasting messages from the one or more additional groups of UEs or additional networks. The aforementioned means may be one or more of the aforementioned components of the apparatus 902 and/or the processing system 1014 of the apparatus 902'configured to perform the functions recited by the aforementioned means. As described supra, the processing system 1014 may include the TX Processor 368, the RX Processor 356, and the controller/processor 359. As such, in one configuration, the aforementioned means may be the TX Processor 368, the RX Processor 356, and the controller/processor 359 configured to perform the functions recited by the aforementioned means.

FIG. 11 is a flowchart 1100 of a method of wireless communication. The method may be performed by a UE (e.g.,

UE

104, 182, 350, 404, 406) in a group UEs (e.g.,

UEs

104, 180, 401, 604, 704, 950) . Optional aspects are illustrated with a dashed line. As mentioned in connection with the example of FIG. 4, the UE can comprise a vehicle and the group UEs can comprise vehicles, respectively. As further mentioned in connection with FIG. 4, these vehicles can travel together in a platooning group. The vehicles (e.g. UE and group UEs) and the platooning group can be part of a V2V communication network. Moreover, the movement of the vehicles can be coordinated based on communication in the V2V communication network. The head UE can use a power control mechanism to control the transmission power of communication or messages within the platooning group.

At 1102, the UE may receive an indication for one or more ACK resources from a head UE in the group of UEs. At 1104, the UE may further receive, from the head UE, a configuration to transmit an ACK or a NAK, wherein the NAK is transmitted on the one or more ACK resources based on the configuration. At 1106, the UE may transmit, on the one or more ACK resources, a NAK to the head UE. The NAK may comprise a UE identifier, as described in connection with FIGs. 4 and 7. In another example, the one or more ACK resources may be common to the group of UEs, and the NAK may be transmitted without a UE identifier. At 1108, the UE may receive an adjustment of a transmit power and/or MCS for the group of UEs from the head UE based, at least in part, on the NAK transmitted to the head UE, e.g., as described at 661 in connection with FIG. 6 or 761 in connection with FIG. 7. The UE may then transmit and/or receive communication with the group of UEs based on the indicated adjustment to the transmit power and/or the MCS.

FIG. 12 is a conceptual data flow diagram 1200 illustrating the data flow between different means/components in an exemplary apparatus 1202. The apparatus may be a UE (e.g.,

UE

104, 182, 350, 404, 406) in a group UEs (e.g.,

UEs

104, 180, 401, 604, 704, 950) . The apparatus includes a reception component 1204 that receives communication from other UEs in the group of UEs and a transmission component 1206 that transmits communication to other UEs in the group of UEs. The communication may be received and/or transmitted based on the types of group messages described in connection with FIG. 5.

The apparatus may include an ACK resource component 1208 configured to receive an indication for one or more ACK resources from a head UE 1250 in the group of UEs. The apparatus may include an ACK/NAK transmission component 1212 configured to transmit, on the one or more ACK resources, a NAK to the head UE. The apparatus may also include an ACK/NAK configuration component 1210 configured to receive, from the head UE 1250, a configuration to transmit an ACK or a NAK, wherein the NAK is transmitted on the one or more ACK resources based on the configuration. The apparatus may further comprise an adjustment component 1214 configured to receive and apply an adjustment of a transmit power and/or MCS from the head UE.

The apparatus may include additional components that perform each of the blocks of the algorithm in the aforementioned flowcharts of FIGs. 6, 7, and 11. As such, each block in the aforementioned flowcharts of FIGs. 6, 7, and 11 may be performed by a component and the apparatus may include one or more of those components. The components may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by a processor configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof.

FIG. 13 is a diagram 1300 illustrating an example of a hardware implementation for an apparatus 1202'employing a processing system 1314. The processing system 1314 may be implemented with a bus architecture, represented generally by the bus 1324. The bus 1324 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 1314 and the overall design constraints. The bus 1324 links together various circuits including one or more processors and/or hardware components, represented by the processor 1304, the

components

1204, 1206, 1208, 1210, 1212, 1214, and the computer-readable medium /memory 1306. The bus 1324 may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The processing system 1314 may be coupled to a transceiver 1310. The transceiver 1310 is coupled to one or more antennas 1320. The transceiver 1310 provides a means for communicating with various other apparatus over a transmission medium. The transceiver 1310 receives a signal from the one or more antennas 1320, extracts information from the received signal, and provides the extracted information to the processing system 1314, specifically the reception component 1204. In addition, the transceiver 1310 receives information from the processing system 1314, specifically the transmission component 1206, and based on the received information, generates a signal to be applied to the one or more antennas 1320. The processing system 1314 includes a processor 1304 coupled to a computer-readable medium /memory 1306. The processor 1304 is responsible for general processing, including the execution of software stored on the computer-readable medium /memory 1306. The software, when executed by the processor 1304, causes the processing system 1314 to perform the various functions described supra for any particular apparatus. The computer-readable medium /memory 1306 may also be used for storing data that is manipulated by the processor 1304 when executing software. The processing system 1314 further includes at least one of the

components

1204, 1206, 1208, 1210, 1212, 1214. The components may be software components running in the processor 1304, resident/stored in the computer readable medium /memory 1306, one or more hardware components coupled to the processor 1304, or some combination thereof. The processing system 1314 may be a component of the UE 350 and may include the memory 360 and/or at least one of the TX processor 368, the RX processor 356, and the controller/processor 359.

In one configuration, the apparatus 1202/1202'for wireless communication includes means for receiving an indication for one or more ACK resources from a head UE in the group of UEs; means for receiving, from the head UE, a configuration to transmit an ACK or a NAK, wherein the NAK is transmitted on the one or more ACK resources based on the configuration; means for transmitting, on the one or more ACK resources, a NAK to the head UE; and means for receiving an adjustment of a transmit power for the group of UEs from the head UE based, at least in part, on the NAK transmitted to the head UE. The aforementioned means may be one or more of the aforementioned components of the apparatus 1202 and/or the processing system 1314 of the apparatus 1202'configured to perform the functions recited by the aforementioned means. As described supra, the processing system 1314 may include the TX Processor 368, the RX Processor 356, and the controller/processor 359. As such, in one configuration, the aforementioned means may be the TX Processor 368, the RX Processor 356, and the controller/processor 359 configured to perform the functions recited by the aforementioned means.

Example 1 is a method of wireless communication at a first UE that includes transmitting an indication for one or more ACK resources for a group of UEs, receiving, on the one or more ACK resources, a first number of NAKs from the group of UEs, and determining whether to adjust a transmit power for transmissions based on the first number of NAKs received on the one or more ACK resources.

In Example 2, the method of the example 1 further includes that the first UE and the group of UEs comprise a platooning group.

In Example 3, the method of any of examples 1-2 further includes that the first UE is a head of the platooning group.

In Example 4, the method of any of examples 1-3 further includes that the first UE comprises a first vehicle and the group of UEs comprise one or more second vehicles, wherein the first vehicle and the one or more second vehicles travel together in the platooning group.

In Example 5, the method of any of examples 1-4 further includes that the first vehicle, the one or more second vehicles, and the platooning group are part of a V2V communication network.

In Example 6, the method of any of examples 1-5 further includes that the movement of the first vehicle and the one or more second vehicles is coordinated based on communication in the V2V communication network.

In Example 7, the method of any of examples 1-6 further includes determining an energy level of the first number of NAKs on the one or more ACK resources, wherein the first UE determines to increase the transmit power when the energy level of the first number of NAKs is greater than a threshold energy level.

In Example 8, the method of any of examples 1-7 further includes that the first UE determines to increase the transmit power based on P _delta = a * (P _NAK –P _Threshold) + b, wherein a and b are constant coefficients, P _delta is power increasing step, P _NAK is the received power of NAK, and P _Threshold is the power of threshold.

In Example 9, the method of any of examples 1-8 further includes configuring at least one UE from the group of UEs to report an ACK or a NAK.

In Example 10, the method of any of examples 1-9 further includes that the at least one UE comprises an edge UE of the group of UEs.

In Example 11, the method of any of examples 1-10 further includes determining an energy level of the first number of NAKs on the one or more ACK resources, wherein the first UE determines to decrease the transmit power when the energy level of the first number of NAKs is less than a threshold energy level.

In Example 12, the method of any of examples 1-11 further includes that the first UE determines to decrease the transmit power based on P _delta = a * (P _NAK –P _Threshold) + b, wherein a and b are constant coefficients, P _delta is power increasing step, P _NAK is the received power of NAK, and P _Threshold is the power of threshold.

In Example 13, the method of any of examples 1-12 further includes that the threshold energy level is preconfigured.

In Example 14, the method of any of examples 1-13 further includes that the threshold energy level is configured by the first UE or a network node.

In Example 15, the method of any of examples 1-14 further includes determining to decrease a MCS when the energy level of the first number of NAKs is greater than the threshold energy level.

In Example 16, the method of any of examples 1-15 further includes receiving, on the one or more ACK resources, a second number of ACKs from the group of UEs, wherein each of the first number of NAKs and second number of ACKs comprises a corresponding UE identifier.

In Example 17, the method of any of examples 1-16 further includes configuring at least one UE from the group of UEs to report an ACK or a NAK.

In Example 18, the method of any of examples 1-17 further includes that the at least one UE comprises an edge UE of the group of UEs.

In Example 19, the method of any of examples 1-18 further includes that the first UE determines to increase the transmit power when the first number of NAKs received from the group of UEs is above a threshold number or when the second number of ACKs received from the group of UEs is below a threshold number.

In Example 20, the method of any of examples 1-19 further includes that the first UE determines to decrease a MCS when the first number of NAKs received from the group of UEs is above a threshold number or when the second number of ACKs received from the group of UEs is below a threshold number.

In Example 21, the method of any of examples 1-20 further includes that the first number of NAKs or the second number of ACKs is determined based on the corresponding UE identifier comprised in each of the first number of NAKs and the second number of ACKs.

In Example 22, the method of any of examples 1-21 further includes that the first UE determines to decrease a transmit power when the first number of NAKs received from the group of UEs is below a threshold number or when the second number of ACKs received from the group of UEs is above a threshold number, wherein the threshold number is based on a threshold energy level or the corresponding UE identifier.

In Example 23, the method of any of examples 1-22 further includes that the first UE determines to increase a MCS when the first number of NAKs received from the group of UEs is below a threshold number or when the second number of ACKs received from the group of UEs is above a threshold number, wherein the threshold number is based on a threshold energy level or the corresponding UE identifier.

In Example 24, the method of any of examples 1-23 further includes that each of the first number of NAKs and the second number of ACKs is scrambled with the corresponding UE identifier.

In Example 25, the method of any of examples 1-24 further includes that the corresponding UE identifier is indicated to the first UE based on a corresponding resource used to receive each of the first number of NAKs or the second number of ACKs.

In Example 26, the method of any of examples 1-25 further includes that the first UE uses a power control mechanism to control the power to transmit one or more messages with the group of UEs.

In Example 27, the method of any of examples 1-26 further includes determining whether one or more additional groups of UEs are within a threshold range of the platooning group.

In Example 28, the method of any of examples 1-27 further includes that determining whether one or more additional groups of UEs are within a threshold range of the platooning group comprises detecting one or more groupcasting messages from the one or more additional groups of UEs or additional networks.

In Example 29, the method of any of examples 1-28 further includes that determining whether one or more additional groups are within a threshold range of the platooning group comprises determining to increase a MCS when the one or more additional groups of UEs are not within the threshold range of the platooning group.

In Example 30, the method of any of examples 1-29 further includes that the one or more ACK resources comprise one or more HARQ resources.

Example 31 is a system or apparatus including means for implementing a method or realizing an apparatus as in any of examples 1-30.

Example 32 is a device including one or more processors and memory in electronic communication with the one or more processors storing instructions executable by the one or more processors to cause the system or apparatus to implement a method as in any of examples 1-30.

Example 33 is a non-transitory computer readable medium storing instructions executable by one or more processors to cause the one or more processors to implement a method as in any of examples 1-30.

Example 34 is a method of wireless communication at a first UE in a group of UEs, comprising receiving an indication for one or more ACK resources from a second UE in the group of UEs, transmitting, on the one or more ACK resources, a NAK to the second UE, and receiving an adjustment of a transmit power for the group of UEs from the second UE based, at least in part, on the NAK transmitted to the second UE.

In Example 35, the method of example 34 further includes receiving, from the head UE, a configuration to transmit an ACK or a NAK, wherein the NAK is transmitted on the one or more ACK resources based on the configuration.

In Example 36, the method of any of examples 34-35 further include that the NAK comprises a UE identifier for the first UE.

In Example 37, the method of any of examples 34-35 further include that the one or more ACK resources are common to the group of UEs, and wherein the NAK is transmitted without a UE identifier.

Example 38 is a system or apparatus including means for implementing a method or realizing an apparatus as in any of examples 34-37.

Example 39 is a device including one or more processors and memory in electronic communication with the one or more processors storing instructions executable by the one or more processors to cause the system or apparatus to implement a method as in any of examples 34-37.

Example 40 is a non-transitory computer readable medium storing instructions executable by one or more processors to cause the one or more processors to implement a method as in any of examples 34-37.

While some specific examples are discussed above, it should be appreciated that many variations are possible. The features discussed in the above examples 1-40 may also be used in combination with any of the other aspects and/or features discussed herein.

It is understood that the specific order or hierarchy of blocks in the processes /flowcharts disclosed is an illustration of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes /flowcharts may be rearranged. Further, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” The word “exemplary” is used herein to mean “serving as an example, instance, or illustration. ” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. The words “module, ” “mechanism, ” “element, ” “device, ” and the like may not be a substitute for the word “means. ” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for. ”

Claims

A method of wireless communication at a first User Equipment (UE) , comprising:

transmitting an indication for one or more acknowledgement (ACK) resources for a group of UEs;

receiving, on the one or more ACK resources, a first number of negative acknowledgements (NAKs) from the group of UEs; and

determining whether to adjust a transmit power for transmissions based on the first number of NAKs received on the one or more ACK resources.
The method of claim 1, wherein the first UE and the group of UEs comprise a platooning group.
The method of claim 2, wherein the first UE is a head of the platooning group.
The method of claim 2, wherein the first UE comprises a first vehicle and the group of UEs comprise one or more second vehicles,

wherein the first vehicle and the one or more second vehicles travel together in the platooning group.
The method of claim 4, wherein the first vehicle, the one or more second vehicles, and the platooning group are part of a vehicle-to-vehicle (V2V) communication network.
The method of claim 5, wherein the movement of the first vehicle and the one or more second vehicles is coordinated based on communication in the V2V communication network.
The method of claim 1, further comprising:

determining an energy level of the first number of NAKs on the one or more ACK resources, wherein the first UE determines to increase the transmit power when the energy level of the first number of NAKs is greater than a threshold energy level.
The method of claim 7, wherein the first UE determines to increase the transmit power based on P _delta = a * (P _NAK –P _Threshold) + b, wherein a and b are constant coefficients, P _delta is power increasing step, P _NAK is the received power of NAK, and P _Threshold is the power of threshold.
The method of claim 7, further comprising;

configuring at least one UE from the group of UEs to report an ACK or a NAK.
The method of claim 9, wherein the at least one UE comprises an edge UE of the group of UEs.
The method of claim 1, further comprising:

determining an energy level of the first number of NAKs on the one or more ACK resources, wherein the first UE determines to decrease the transmit power when the energy level of the first number of NAKs is less than a threshold energy level.
The method of claim 11, wherein the first UE determines to decrease the transmit power based on P _delta = a * (P _NAK –P _Threshold) + b, wherein a and b are constant coefficients, P _delta is power increasing step, P _NAK is the received power of NAK, and P _Threshold is the power of threshold.
The method of claim 7, wherein the threshold energy level is preconfigured.
The method of claim 7, wherein the threshold energy level is configured by the first UE or a network node.
The method of claim 7, further comprising:

determining to decrease a modulation and coding scheme (MCS) when the energy level of the first number of NAKs is greater than the threshold energy level.
The method of claim 1, further comprising:

receiving, on the one or more ACK resources, a second number of ACKs from the group of UEs, wherein each of the first number of NAKs and second number of ACKs comprises a corresponding UE identifier.
The method of claim 16, further comprising;

configuring at least one UE from the group of UEs to report an ACK or a NAK.
The method of claim 17, wherein the at least one UE comprises an edge UE of the group of UEs.
The method of claim 16, wherein the first UE determines to increase the transmit power when the first number of NAKs received from the group of UEs is above a threshold number or when the second number of ACKs received from the group of UEs is below a threshold number.
The method of claim 16, wherein the first UE determines to decrease a MCS when the first number of NAKs received from the group of UEs is above a threshold number or when the second number of ACKs received from the group of UEs is below a threshold number.
The method of claim 16, wherein the first number of NAKs or the second number of ACKs is determined based on the corresponding UE identifier comprised in each of the first number of NAKs and the second number of ACKs.
The method of claim 16, wherein the first UE determines to decrease a transmit power when the first number of NAKs received from the group of UEs is below a threshold number or when the second number of ACKs received from the group of UEs is above a threshold number,

wherein the threshold number is based on a threshold energy level or the corresponding UE identifier.
The method of claim 16, wherein the first UE determines to increase a MCS when the first number of NAKs received from the group of UEs is below a threshold number or when the second number of ACKs received from the group of UEs is above a threshold number,

wherein the threshold number is based on a threshold energy level or the corresponding UE identifier.
The method of claim 16, wherein each of the first number of NAKs and the second number of ACKs is scrambled with the corresponding UE identifier.
The method of claim 16, wherein the corresponding UE identifier is indicated to the first UE based on a corresponding resource used to receive each of the first number of NAKs or the second number of ACKs.
The method of claim 1, wherein the first UE uses a power control mechanism to control the power to transmit one or more messages with the group of UEs.
The method of claim 1, further comprising:

determining whether one or more additional groups of UEs are within a threshold range of the platooning group.
The method of claim 27, wherein determining whether one or more additional groups of UEs are within a threshold range of the platooning group comprises:

detecting one or more groupcasting messages from the one or more additional groups of UEs or additional networks.
The method of claim 27, wherein determining whether one or more additional groups are within a threshold range of the platooning group comprises:

determining to increase a MCS when the one or more additional groups of UEs are not within the threshold range of the platooning group.
The method of claim 1, wherein the one or more ACK resources comprise one or more hybrid automatic repeat request (HARQ) resources.
An apparatus for wireless communication at a first User Equipment (UE) , comprising:

means for transmitting an indication for one or more acknowledgement (ACK) resources for a group of UEs;

means for receiving, on the one or more ACK resources, a first number of negative acknowledgements (NAKs) from the group of UEs; and

means for determining whether to adjust a transmit power for transmissions based on the first number of NAKs received on the one or more ACK resources.
The apparatus of claim 31, wherein the first UE and the group of UEs comprise a platooning group.
The apparatus of claim 32, wherein the first UE is a head of the platooning group.
The apparatus of claim 32, wherein the first UE comprises a first vehicle and the group of UEs comprise one or more second vehicles,

wherein the first vehicle and the one or more second vehicles travel together in the platooning group.
The apparatus of claim 34, wherein the first vehicle, the one or more second vehicles, and the platooning group are part of a vehicle-to-vehicle (V2V) communication network.
The apparatus of claim 35, wherein the movement of the first vehicle and the one or more second vehicles is coordinated based on communication in the V2V communication network.
The apparatus of claim 31, further comprising:

means for determining an energy level of the first number of NAKs on the one or more ACK resources, wherein the first UE determines to increase the transmit power when the energy level of the first number of NAKs is greater than a threshold energy level.
The apparatus of claim 37, wherein the first UE determines to increase the transmit power based on P _delta = a * (P _NAK –P _Threshold) + b, wherein a and b are constant coefficients, P _delta is power increasing step, P _NAK is the received power of NAK, and P _Threshold is the power of threshold.
The apparatus of claim 37, further comprising;

means for configuring at least one UE from the group of UEs to report an ACK or a NAK.
The apparatus of claim 39, wherein the at least one UE comprises an edge UE of the group of UEs.
The apparatus of claim 31, further comprising:

means for determining an energy level of the first number of NAKs on the one or more ACK resources, wherein the first UE determines to decrease the transmit power when the energy level of the first number of NAKs is less than a threshold energy level.
The apparatus of claim 41, wherein the first UE determines to decrease the transmit power based on P _delta = a * (P _NAK –P _Threshold) + b, wherein a and b are constant coefficients, P _delta is power increasing step, P _NAK is the received power of NAK, and P _Threshold is the power of threshold.
The apparatus of claim 37, wherein the threshold energy level is preconfigured.
The apparatus of claim 37, wherein the threshold energy level is configured by the first UE or a network node.
The apparatus of claim 37, further comprising:

means for determining to decrease a modulation and coding scheme (MCS) when the energy level of the first number of NAKs is greater than the threshold energy level.
The apparatus of claim 31, further comprising:

means for receiving, on the one or more ACK resources, a second number of ACKs from the group of UEs, wherein each of the first number of NAKs and second number of ACKs comprises a corresponding UE identifier.
The apparatus of claim 46, further comprising;

means for configuring at least one UE from the group of UEs to report an ACK or a NAK.
The apparatus of claim 47, wherein the at least one UE comprises an edge UE of the group of UEs.
The apparatus of claim 46, wherein the first UE determines to increase the transmit power when the first number of NAKs received from the group of UEs is above a threshold number or when the second number of ACKs received from the group of UEs is below a threshold number.
The apparatus of claim 46, wherein the first UE determines to decrease a MCS when the first number of NAKs received from the group of UEs is above a threshold number or when the second number of ACKs received from the group of UEs is below a threshold number.
The apparatus of claim 46, wherein the first number of NAKs or the second number of ACKs is determined based on the corresponding UE identifier comprised in each of the first number of NAKs and the second number of ACKs.
The apparatus of claim 46, wherein the first UE determines to decrease a transmit power when the first number of NAKs received from the group of UEs is below a threshold number or when the second number of ACKs received from the group of UEs is above a threshold number,

wherein the threshold number is based on a threshold energy level or the corresponding UE identifier.
The apparatus of claim 46, wherein the first UE determines to increase a MCS when the first number of NAKs received from the group of UEs is below a threshold number or when the second number of ACKs received from the group of UEs is above a threshold number,

wherein the threshold number is based on a threshold energy level or the corresponding UE identifier.
The apparatus of claim 46, wherein each of the first number of NAKs and the second number of ACKs is scrambled with the corresponding UE identifier.
The apparatus of claim 46, wherein the corresponding UE identifier is indicated to the first UE based on a corresponding resource used to receive each of the first number of NAKs or the second number of ACKs.
The apparatus of claim 31, wherein the first UE uses a power control mechanism to control the power to transmit one or more messages with the group of UEs.
The apparatus of claim 31, further comprising:

means for determining whether one or more additional groups of UEs are within a threshold range of the platooning group.
The apparatus of claim 57, wherein means for determining whether one or more additional groups of UEs are within a threshold range of the platooning group is configured to:

detect one or more groupcasting messages from the one or more additional groups of UEs or additional networks.
The apparatus of claim 57, wherein means for determining whether one or more additional groups are within a threshold range of the platooning group is configured to:

determine to increase a MCS when the one or more additional groups of UEs are not within the threshold range of the platooning group.
The apparatus of claim 31, wherein the one or more ACK resources comprise one or more hybrid automatic repeat request (HARQ) resources.
An apparatus for wireless communication at a first User Equipment (UE) , comprising:

a memory; and

at least one processor coupled to the memory and configured to:

transmit an indication for one or more acknowledgement (ACK) resources for a group of UEs;

receive, on the one or more ACK resources, a first number of negative acknowledgements (NAKs) from the group of UEs; and

determine whether to adjust a transmit power for transmissions based on the first number of NAKs received on the one or more ACK resources.
The apparatus of claim 61, wherein the first UE and the group of UEs comprise a platooning group.
The apparatus of claim 62, wherein the first UE is a head of the platooning group.
The apparatus of claim 62, wherein the first UE comprises a first vehicle and the group of UEs comprise one or more second vehicles,

wherein the first vehicle and the one or more second vehicles travel together in the platooning group.
The apparatus of claim 64, wherein the first vehicle, the one or more second vehicles, and the platooning group are part of a vehicle-to-vehicle (V2V) communication network.
The apparatus of claim 65, wherein the movement of the first vehicle and the one or more second vehicles is coordinated based on communication in the V2V communication network.
The apparatus of claim 61, wherein the at least one processor is further configured to:

determine an energy level of the first number of NAKs on the one or more ACK resources, wherein the first UE determines to increase the transmit power when the energy level of the first number of NAKs is greater than a threshold energy level.
The apparatus of claim 67, wherein the first UE determines to increase the transmit power based on P _delta = a * (P _NAK –P _Threshold) + b, wherein a and b are constant coefficients, P _delta is power increasing step, P _NAK is the received power of NAK, and P _Threshold is the power of threshold.
The apparatus of claim 67, wherein the at least one processor is further configured to:

configure at least one UE from the group of UEs to report an ACK or a NAK.
The apparatus of claim 69, wherein the at least one UE comprises an edge UE of the group of UEs.
The apparatus of claim 61, wherein the at least one processor is further configured to:

determine an energy level of the first number of NAKs on the one or more ACK resources, wherein the first UE determines to decrease the transmit power when the energy level of the first number of NAKs is less than a threshold energy level.
The apparatus of claim 71, wherein the first UE determines to decrease the transmit power based on P _delta = a * (P _NAK –P _Threshold) + b, wherein a and b are constant coefficients, P _delta is power increasing step, P _NAK is the received power of NAK, and P _Threshold is the power of threshold.
The apparatus of claim 67, wherein the threshold energy level is preconfigured.
The apparatus of claim 67, wherein the threshold energy level is configured by the first UE or a network node.
The apparatus of claim 67, wherein the at least one processor is further configured to:

determine to decrease a modulation and coding scheme (MCS) when the energy level of the first number of NAKs is greater than the threshold energy level.
The apparatus of claim 61, wherein the at least one processor is further configured to:

receive, on the one or more ACK resources, a second number of ACKs from the group of UEs, wherein each of the first number of NAKs and second number of ACKs comprises a corresponding UE identifier.
The apparatus of claim 76, wherein the at least one processor is further configured to:

configure at least one UE from the group of UEs to report an ACK or a NAK.
The apparatus of claim 77, wherein the at least one UE comprises an edge UE of the group of UEs.
The apparatus of claim 76, wherein the first UE determines to increase the transmit power when the first number of NAKs received from the group of UEs is above a threshold number or when the second number of ACKs received from the group of UEs is below a threshold number.
The apparatus of claim 76, wherein the first UE determines to decrease a MCS when the first number of NAKs received from the group of UEs is above a threshold number or when the second number of ACKs received from the group of UEs is below a threshold number.
The apparatus of claim 76, wherein the first number of NAKs or the second number of ACKs is determined based on the corresponding UE identifier comprised in each of the first number of NAKs and the second number of ACKs.
The apparatus of claim 76, wherein the first UE determines to decrease a transmit power when the first number of NAKs received from the group of UEs is below a threshold number or when the second number of ACKs received from the group of UEs is above a threshold number,

wherein the threshold number is based on a threshold energy level or the corresponding UE identifier.
The apparatus of claim 76, wherein the first UE determines to increase a MCS when the first number of NAKs received from the group of UEs is below a threshold number or when the second number of ACKs received from the group of UEs is above a threshold number,

wherein the threshold number is based on a threshold energy level or the corresponding UE identifier.
The apparatus of claim 76, wherein each of the first number of NAKs and the second number of ACKs is scrambled with the corresponding UE identifier.
The apparatus of claim 76, wherein the corresponding UE identifier is indicated to the first UE based on a corresponding resource used to receive each of the first number of NAKs or the second number of ACKs.
The apparatus of claim 61, wherein the first UE uses a power control mechanism to control the power to transmit one or more messages with the group of UEs.
The apparatus of claim 61, wherein the at least one processor is further configured to:

determine whether one or more additional groups of UEs are within a threshold range of the platooning group.
The apparatus of claim 87, wherein to determine whether one or more additional groups of UEs are within a threshold range of the platooning group further comprises the at least one processor configured to:

detect one or more groupcasting messages from the one or more additional groups of UEs or additional networks.
The apparatus of claim 87, wherein to determine whether one or more additional groups are within a threshold range of the platooning group further comprises the at least one processor configured to:

determine to increase a MCS when the one or more additional groups of UEs are not within the threshold range of the platooning group.
The apparatus of claim 61, wherein the one or more ACK resources comprise one or more hybrid automatic repeat request (HARQ) resources.
A computer-readable medium storing computer executable code, comprising code to:

transmit an indication for one or more acknowledgement (ACK) resources for a group of UEs;

receive, on the one or more ACK resources, a first number of negative acknowledgements (NAKs) from the group of UEs; and

determine whether to adjust a transmit power for transmissions based on the first number of NAKs received on the one or more ACK resources.
A method of wireless communication at a first User Equipment (UE) in a group of UEs, comprising:

receiving an indication for one or more acknowledgement (ACK) resources from a head UE in the group of UEs;

transmitting, on the one or more ACK resources, a negative acknowledgement (NAK) to the head UE; and

receiving an adjustment of a transmit power for the group of UEs from the head UE based, at least in part, on the NAK transmitted to the head UE.
The method of claim 92, wherein the NAK comprises a UE identifier for the first UE.
The method of claim 92, wherein the one or more ACK resources are common to the group of UEs, and wherein the NAK is transmitted without a UE identifier.
The method of claim 92, further comprising:

receiving, from the head UE, a configuration to transmit an ACK or a NAK, wherein the NAK is transmitted on the one or more ACK resources based on the configuration.